1. Field of the Invention
The present invention relates to an image pickup apparatus, and more particularly, it relates to an image pickup apparatus increasing charges stored in pixels.
2. Description of the Background Art
An image pickup apparatus increasing charges stored in pixels is known in general.
A CCD (charge coupled device) image pickup apparatus comprising four gate electrodes, in which a pixel separation barrier, a charge temporary storage well, a charge transfer barrier and a charge accumulation well are formed under the respective gate electrodes, is known in general. In this CCD image pickup apparatus, a high-field region is formed adjacent to each other on an interface between the charge transfer barrier and the charge accumulation well. When charges stored in the temporary storage well pass over the charge transfer barrier and move to the charge accumulation well, the charges are increased in the high-field region by collisional ionization. In this CCD image pickup apparatus, the intensity of an electric field of the high-field region of a frame just after a last frame is controlled as proportional to the luminance value of the last frame. Thus, sensitivity of the CCD image pickup apparatus can be improved.